Risk factors for severe delayed postpolypectomy bleeding.

BACKGROUND AND STUDY AIMS: Postpolypectomy bleeding is a rare but serious adverse event. The aim of this study was to identify factors associated with the risk of severe delayed postpolypectomy bleeding. PATIENTS AND METHODS: This was a case-control study, comparing cases who developed hematochezia and required medical evaluation 6 hours to 14 days after colonoscopic polypectomy, and control patients who underwent polypectomy without delayed bleeding, and who were selected in approximately a 3 : 1 ratio. The following risk factors were specified a priori: resuming anticoagulation (within 1 week following polypectomy), aspirin use, hypertension, and polyp diameter. RESULTS: Of the 4592 patients who underwent colonoscopy with polypectomy, 41 patients (0.9 %) developed delayed postpolypectomy bleeding (cases), and 132 patients were selected as controls. The mean age was 64.3 years for cases and 65.4 years for controls. Cases presented on average 6 days after polypectomy (range 1 - 14 days), and 48 % required blood transfusion (average 4.2 units, range 0 - 17). Two patients required surgery. Anticoagulation was resumed following polypectomy in 34 % of cases compared with 9 % of controls (OR 5.2; 95 % CI 2.2 - 12.5; P < 0.001). For every 1 mm increase in polyp diameter, the risk of hemorrhage increased by 9 % (OR 1.09; 95 % CI 1.0 - 1.2; P = 0.008). Hypertension (OR 1.1) and aspirin use (OR 1.1) did not increase the risk of postpolypectomy bleeding. In exploratory analysis, diabetes (OR 2.5) and coronary artery disease (OR 3.0) were associated with postpolypectomy hemorrhage, but the association was no longer statistically significant once adjusted for the use of anticoagulation. CONCLUSIONS: Resuming anticoagulation following polypectomy and polyp diameter were strongly associated with increased risk of severe delayed postpolypectomy bleeding.

Quality in the technical performance of screening flexible sigmoidoscopy: recommendations of an international multi-society task group.

BACKGROUND: Flexible sigmoidoscopy (FS) is a complex technical procedure performed in a variety of settings, by examiners with diverse professional backgrounds, training, and experience. Potential variation in technical quality may have a profound impact on the effectiveness of FS on the early detection and prevention of colorectal cancer. AIM: We propose a set of consensus and evidence based recommendations to assist the development of continuous quality improvement programmes around the delivery of FS for colorectal cancer screening. RECOMMENDATIONS: These recommendations address the intervals between FS examinations, documentation of results, training of endoscopists, decision making around referral for colonoscopy, policies for antibiotic prophylaxis and management of anticoagulation, insertion of the FS endoscope, bowel preparation, complications, the use of non-physicians as FS endoscopists, and FS endoscope reprocessing. For each of these areas, continuous quality improvement targets are recommended, and research questions are proposed.

Colon polyps and cancer.

The role of endoscopy, in particular colonoscopy, clearly is paramount in the screening, diagnosis, and prevention of colorectal cancer. In preparation for writing this "state-of-the-art" review on colon polyps and cancer, a PubMed literature search linking the topic with endoscopy yielded an enormous number of papers published in peer-reviewed journals just in the past 12 months. I have selected a few of these to highlight that I believe are most germane to current issues of risk stratification, screening and surveillance, prevention, and the premalignant potential of different types of adenomas detected by endoscopy. Several of these papers address the advantages and limitations of direct colonoscopy screening for colorectal neoplasia, and discuss the emerging role of virtual colonoscopy screening.

Colon polyps and cancer.

A large number of studies published last year in peer-reviewed medical journals help to better define the advantages and limitations of the different options for colorectal cancer screening. Direct colonoscopy screening appears to have the greatest potential to markedly reduce both the incidence and mortality of colorectal cancer, but many obstacles limiting its widespread use in the general at-risk population still exist, and many questions remain incompletely answered. Recent studies stress the fact that finding and resecting advanced adenomatous polyps, and thereby preventing cancer, is becoming a primary objective of screening programs. Several papers also show the potential of emerging new methods of screening for specific markers in stool and for imaging the colon with computed-tomographic colonography (virtual colonoscopy). Other important publications highlighted in this review deal with the diagnosis of colorectal neoplasia, familial colorectal cancer, colorectal polyps and the adenoma-carcinoma sequence, and new and novel methods of improving the efficiency and safety of colonoscopic polypectomy.

Medical-legal risks of incident cancers after clearing colonoscopy.

Colonoscopy and polypectomy effectively reduce the incidence and mortality of colorectal cancer, but some patients present with fully developed cancers within 1-4 yr of a colonoscopy that apparently cleared the colon of neoplasia. These events may result in medical-legal action against colonoscopists, generally based on an assumption of negligent technical performance of the procedure. Alternative explanations for the development of interval cancers include variable growth rates of colorectal cancers, the inherent miss rate of the procedure even when optimal examination techniques are used, and the possibility of flat lesions that are not readily detected by standard colonoscopic techniques. This paper discusses issues relevant to reduction of medical-legal risks associated with interval cancers after clearing colonoscopy. These issues include informed consent, documentation of cecal intubation, appropriate description of preparation, documentation of examination time and technique, and attention to potential atypical neoplasms.

Colon polyps and cancer.

During 1999-2000, a number of important issues related to endoscopy and colorectal polyps and cancer were investigated. Several papers consider whether flat adenomas with high malignant potential are as common in the West as in Japan. Clinical series indicate that signs of rectal bleeding are more predictive of colorectal cancer than gastrointestinal symptoms. Colonoscopy is more accurate than double-contrast barium enema for detecting polyps, and virtual colonoscopy is a promising new diagnostic and screening technique. Primary prevention dietary studies using adenoma recurrence as an end point yield negative results. Surveillance colonoscopy protects individuals in families with hereditary nonpolyposis colorectal cancer, but gastroenterologists continue to perform cancer surveillance in patients with ulcerative colitis in an inconsistent manner. Screening for colorectal neoplasia with fecal occult blood tests and flexible sigmoidoscopy is being better defined and promoted, although many now advocate direct colonoscopy screening based on increasing indirect evidence of efficacy. Better methods of treating large sessile neoplasms are being developed and evaluated, and follow-up surveillance for adenoma patients increasingly is being tailored to individual patient risk.

The effect of fecal occult-blood screening on the incidence of colorectal cancer.

BACKGROUND: Both annual testing for fecal occult blood and biennial testing significantly reduce mortality from colorectal cancer. However, the effect of screening on the incidence of colorectal cancer remains uncertain, despite the diagnosis and removal of precancerous lesions in many persons who undergo screening. METHODS: We followed the participants in the Minnesota Colon Cancer Control Study for 18 years. A total of 46,551 people, most of whom were 50 to 80 years old, were enrolled between 1975 and 1978 and randomly assigned to annual screening, biennial screening, or usual care (the control group). Those assigned to the screening groups were asked to prepare and submit two samples from each of three consecutive stools for guaiac-based testing. Those with at least one positive slide in the set of six were offered a diagnostic examination that included colonoscopy. Screening was conducted between 1976 and 1982 and again between 1986 and 1992. Study participants have been followed with respect to newly diagnosed cases of colorectal cancer and deaths. Follow-up has been more than 90 percent complete. RESULTS: During the 18-year follow-up period, we identified 1359 new cases of colorectal cancer: 417 in the annual-screening group, 435 in the biennial-screening group, and 507 in the control group. The cumulative incidence ratios for colorectal cancer in the screening groups as compared with the control group were 0.80 (95 percent confidence interval, 0.70 to 0.90) and 0.83 (95 percent confidence interval, 0.73 to 0.94) for the annual-screening and biennial-screening groups, respectively. For both screening groups, the number of positive slides was associated with the positive predictive value both for colorectal cancer and for adenomatous polyps at least 1 cm in diameter. CONCLUSIONS: The use of either annual or biennial fecal occult-blood testing significantly reduces the incidence of colorectal cancer.

Clinical evidence for the adenoma-carcinoma sequence, and the management of patients with colorectal adenomas.

A large body of clinical evidence supports the belief that over 95% of colorectal cancers arise in benign adenomatous polyps that develop and grow very slowly over many years. Interruption of the adenoma-carcinoma sequence by resecting adenomatous polyps is a powerful method of secondary prevention of colorectal cancer. Colonoscopy is the procedure of choice for the diagnosis and resection of colorectal polyps. Patients who have had colonoscopic resection of adenomas, and in some cases their close relatives, are at increased risk for developing metachronous polyps and cancer and may benefit from follow-up colonoscopic surveillance. This surveillance should be individually tailored to the perceived risk of each case depending on the features of the adenomas removed and other patient factors such as family history. Widespread adoption of current postpolypectomy guideline recommendations is protective and conserves medical resources.

Colorectal cancer update. Prevention, screening, treatment, and surveillance for high-risk groups.

Great advances have been made in understanding the cause and molecular genesis of colorectal cancer. The disease can be prevented by a healthful diet and lifestyle or by resecting the precursor of most of these cancers, the advanced adenomatous polyp. Screening the average-risk population plus special surveillance for high-risk groups now is recommended by evidence-based guidelines. Surgery is highly curative for patients without distant metastases, and adjuvant therapy improves survival in selected patients with advanced cancers.

Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380.

BACKGROUND AND METHODS: The role of colonoscopy in screening for colorectal cancer is uncertain. At 13 Veterans Affairs Medical Centers, we performed colonoscopy to determine the prevalence and location of advanced colonic neoplasms and the risk of advanced proximal neoplasia in asymptomatic patients (age range, 50 to 75 years) with or without distal neoplasia. Advanced colonic neoplasia was defined as an adenoma that was 10 mm or more in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. In patients with more than one neoplastic lesion, classification was based on the most advanced lesion. RESULTS: Of 17,732 patients screened for enrollment, 3196 were enrolled; 3121 of the enrolled patients (97.7 percent) underwent complete examination of the colon. The mean age of the patients was 62.9 years, and 96.8 percent were men. Colonoscopic examination showed one or more neoplastic lesions in 37.5 percent of the patients, an adenoma with a diameter of at least 10 mm or a villous adenoma in 7.9 percent, an adenoma with high-grade dysplasia in 1.6 percent, and invasive cancer in 1.0 percent. Of the 1765 patients with no polyps in the portion of the colon that was distal to the splenic flexure, 48 (2.7 percent) had advanced proximal neoplasms. Patients with large adenomas (> or = 10 mm) or small adenomas (< 10 mm) in the distal colon were more likely to have advanced proximal neoplasia than were patients with no distal adenomas (odds ratios, 3.4 [95 percent confidence interval, 1.8 to 6.5] and 2.6 (95 percent confidence interval, 1.7 to 4.1], respectively). However, 52 percent of the 128 patients with advanced proximal neoplasia had no distal adenomas. CONCLUSIONS: Colonoscopic screening can detect advanced colonic neoplasms in asymptomatic adults. Many of these neoplasms would not be detected with sigmoidoscopy.

A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group.

BACKGROUND: After patients have undergone colonoscopic polypectomy, it is uncertain whether colonoscopic examination or a barium enema is the better method of surveillance. METHODS: As part of the National Polyp Study, we offered colonoscopic examination and double-contrast barium enema for surveillance to patients with newly diagnosed adenomatous polyps. Although barium enema was performed first, the endoscopist did not know the results. RESULTS: A total of 973 patients underwent one or more colonoscopic examinations for surveillance. In the case of 580 of these patients, we performed 862 paired colonoscopic examinations and barium-enema examinations that met the requirements of the protocol. The findings on barium enema were positive in 222 (26 percent) of the paired examinations, including 139 of the 392 colonoscopic examinations in which one or more polyps were detected (rate of detection, 35 percent; 95 percent confidence interval, 31 to 40 percent). The proportion of examinations in which adenomatous polyps were detected by barium enema colonoscopy was significantly related to the size of the adenomas (P=0.009); the rate was 32 percent for colonoscopic examinations in which the largest adenomas detected were 0.5 cm or less, 53 percent for those in which the largest adenomas detected were 0.6 to 1.0 cm, and 48 percent for those in which the largest adenomas detected exceeded 1.0 cm. Among the 139 paired examinations with positive results on barium enema and negative results on colonoscopic examination in the same location, 19 additional polyps, 12 of which were adenomas, were detected on colonoscopic reexamination. CONCLUSIONS: In patients who have undergone colonoscopic polypectomy, colonoscopic examination is a more effective method of surveillance than double-contrast barium enema.